The present invention generally relates to modular, central-frame, offset, dual control arm independent suspension and suspension retrofit. More specifically, the present invention relates to modular, central-frame, offset, dual controlarm independent suspension and suspension retrofit which may be incorporated into and/or may be attached to an independent suspension vehicle. The dual control-arm independent suspension may be fixed to and/or may be attached to the central tubular frame. Control-arm pivot positions may be integral to a centrally mounted differential housing to permit an upper control arm geometry and/or a lower control arm geometry relative to the central tubular frame. An integral jounce and/or a rebound stop may be located within the centrally mounted differential housing to support a cargo body and/or an upper vehicle structure. Alternatively, a frame mounted jounce limiter may be located along a space frame fixed to a suspension tube to support the cargo body and/or the upper vehicle structure.
A power transmission may be located within the central tubular frame for providing power transmitting shafts from the transmission to the axle units and/or the suspension units. Wheel positions and/or control arm geometries may be offset from a first side to a second side along a length of the independent suspension vehicle. The dual control arm independent suspension may have spring elements attachable to central tubular frame, to an accessory frame and/or to the differential housing. A joint and/or an angular power transmission element may be attached to an outboard end of a centrally pivoted axle driveshaft to accommodate extension or compression of a half shaft during suspension travel. A knuckle and/or a wheel planetary assembly with or without final drive reduction may be attached to the dual control arm independent suspension. The wheel assembly may provide and/or may be attachable to components, such as, for example, outboard control arm pivots, a steering arm, a spindle, wheel bearings, a brake spider and/or brake elements.
It is generally known that a vehicle manufacturer provides a central tube to form a structural frame of a vehicle and/or a backbone to support a swing arm vehicle suspension. The central tube provides a protective housing for power transmitting shafts and/or drive-train elements. Typically, flanged tubular frame sections of the central tube are fastened to mate with axially centered differential housings. Swing arms of the swing arm vehicle suspension pivot with respect to a center axis of the differential housing to protrude at right angles with respect to the differential housings. As a result, an offset is provided across a width of the vehicle to drive opposing output shaft pinions from an axially mounted differential ring gear. A dual control arm independent suspension is attachable to the differential housings below a ladder-type structural frame of the vehicle. As a result, control arms and/or half shaft geometry of the dual control arm independent suspension locate and/or provide a symmetric tire contact patch across the width of the vehicle.
However, the swing arm vehicle suspension has limited kinematic possibilities. For example, the swing arm vehicle suspension provides geometry forces of a wheel and/or a tire to travel through a circular arc with simultaneously changing a tire camber angle and/or a tire contact patch location via a suspension motion. Changes in camber angle and/or tire contact patch location during suspension trave is an undesirable characteristic which results in poor handling, excessive tire-wear or a “jacking” and/or a lifting of the vehicle body upward while negotiating curves. Further, a suspension element of the swing arm vehicle suspension must be fixed to a central structure which prevents dual control arm independent suspension elements from being incorporated into the swing arm vehicle suspension.
A need, therefore, exists for modular, central-frame, offset, dual control arm independent suspension and suspension retrofit. Additionally, a need exists for modular, central frame, offset, dual control arm independent suspension and suspension retrofit which may provide elements of a tubular frame chassis to maximize kinematic possibilities and/or to improve handling and/or wheel travel properties of the dual control arm independent suspensions. Further, a need exists for modular, central frame, offset, dual control arm independent suspension and suspension retrofit which may provide a suspension and/or a chassis to negotiate rough terrain at high speeds with improved ride comfort and/or safety while remaining within legal parameters and/or suspension performance parameters. Still further, a need exists for modular, central frame, an offset, dual control arm independent suspension and suspension retrofit which may provide an integral central protective housing for power transmitting shafts and/or drive train elements via the central frame.